*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
div{
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
    width: 300px;
    height: 300px;
    border-radius: 50%;
    box-shadow: 0 0 0 15px #03a9f4;
    background: #fff;
    box-sizing: border-box;
    text-align: center;
    transition: .5s;
}
div:hover
{
    border-radius: 0;

}
div::before{
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #03a9f4;
    z-index: -1;
    transform: rotate(45deg);
    border-radius: 10px;
}
div p{
    position: absolute;
    margin: 0;
    padding: 20px;
    color: #fff;
    font-size: 16px;
    top: 50%;
    transform: translateY(-50%);
    transition: .5s;
    pointer-events: none;
}
div:hover p{
    box-shadow: 0 0 50px rgba(0,0,0,.5);
}


